Congenital Gynecologic Defects and Müllerian Anomalies

Question 1

What are the four steps of Müllerian development?

Answer 1

1) Elongation (growing down from the mesonephros to the urogenital sinus)
2) Fusion (the left and right halves coming together)
3) Canalization (because the structures are initially solid)
4) Septal resorption
5) Union with sinovaginal bulb (aka urogenital sinus)

Question 2

The Müllerian ducts are just ______________ to the mesonephros.

Answer 2

lateral

Question 3

If a woman presents with a transverse septum in her vagina –that blocks passage to her uterus –what embryologic structure likely gave rise to this?

Answer 3

The distal tip of the paramesonephric duct has failed to canalize with the urogenital sinus

Question 4

Müllerian defects are almost always separate from _________________.

Answer 4

ovarian defects: so patients with Müllerian defects will have normal gonadal/secondary sexual development

Question 5

Müllerian agenesis is a disorder of which step in Müllerian development?

Answer 5

Elongation

Question 6

Uterine didelphys is _____________.

Answer 6

class III uterine Müllerian hypoplasia

Question 7

Uterine didelphys results from a failure of _____________.

Answer 7

fusion

Question 8

Uterine didelphys with obstructed hemivagina will present with ______________.

Answer 8

pain, because women will bleed but the blood cannot leave the body

Question 9

_____________ is another kind of failure of uterine fusion (in addition to uterine didelphys).

Answer 9

Bicornuate uterus

Question 10

Normally, the __________ is partially perforated.

Answer 10

hymen

Question 11

True or false: a woman presenting to the Emergency Room with imperforate hymen should be canalized and sent home.

Answer 11

False. The vagina has commensal bacteria, and inserting a needle through an imperforate hymen will bring bacteria into the walled-off uterus. An infection will result. As such, close monitoring after surgical intervention in cases of an imperforate hymen is needed.

Question 12

Neural crest cells are derived from ______________.

Answer 12

neural ectoderm

Question 13

What embryonic gives rise to the gonads?

Answer 13

Intermediate mesoderm

Question 14

True or false: the kidneys form from a structure that branches off of the structure that becomes the fallopian tube.

Answer 14

False. The ureteric bud (metanephros) branches off of the mesonephros, which becomes the ductus deferens in males.

Question 15

The mesonephric duct is ____________ to the paramesonephric duct.

Answer 15

medial (meso = medial)

Question 16

Unicornuate uterus results from failure of ________________.

Answer 16

elongation

Question 17

Imperforate hymen results from a defect in what embryonic structure?

Answer 17

Sino-vaginal bulb

Question 18

Prior to canalizing an imperforate hymen, you need to verify (via imaging) that it is not a ___________________.

Answer 18

transverse vaginal septum

Question 19

What kind of failure results in class I or II Müllerian anomalies?

Answer 19

Failure of elongation (I = bilateral; II = unilateral)

Question 20

Failure of fusion results in which types of Müllerian anomalies?

Answer 20

III (uterine didelphys, with two distinct uteruses and cervixes) and IV (bicornuate uterus, with two cavities but only one cervix)